Preliminary results on detection of neurotransmitter serotonin using an electrochemical sensor, based on a composite made of core-shell molecularly imprinted polymer (MIP) nanoparticles and polyethylenedioxythiophene (PEDOT) film are described. MIP is grown on pre-formed SiO2 nanobeads by surface imprinting via reversible addition-fragmentation chain-transfer (RAFT) polymerization. The core-shell Ser-MIP@SiO2 nanobeads are integrated onto electrode surfaces to develop an electrochemical sensors for analyte serotonin. The entrapment of core-shell Ser-MIP@SiO2 nanobeads by the electropolymerization of PEDOT in an upside-down electrochemical cell is performed and preliminary results in sensing application are presented.